Abstract: A steam circuit is defined in a multi-section single shaft turbine. A hot reheat steam is input to a section of the multi-section turbine. A first flow path flows the hot reheat steam from an upstream side through the section of the multi-section turbine to a downstream side to create work. A second flow path directs a portion of the flow back toward the upstream side in the section of the multi-section turbine between an outer shell and an inner shell of the turbine. The effective shell cooling provides for increased main and reheat steam temperatures to improve performance. The system reduces the extraction steam flow required to meet the design final feedwater temperatures and allows more steam to expand through the low pressure section.

Abstract: A steam circuit is defined in a multi-section single shaft turbine. A hot reheat steam is input to a section of the multi-section turbine. A first flow path flows the hot reheat steam from an upstream side through the section of the multi-section turbine to a downstream side to create work. A second flow path directs a portion of the flow back toward the upstream side in the section of the multi-section turbine between an outer shell and an inner shell of the turbine. The effective shell cooling provides for increased main and reheat steam temperatures to improve performance. The system reduces the extraction steam flow required to meet the design final feedwater temperatures and allows more steam to expand through the low pressure section.

Abstract: A double flow low-pressure (LP) steam turbine with an LP section that can be engaged and disengaged from a drive train is provided, as are methods for its use. In one embodiment, the invention provides a steam turbine comprising: a high pressure (HP) section; an intermediate pressure (IP) section adjacent the HP section; a first low pressure (LP) section; a second LP section; a crossover pipe connecting the IP section to the first LP section and the second LP section; a drive train extending through the HP section, the IP section, the first LP section, and the second LP section; a device for engaging and disengaging the second LP section from the drive train; a valve for alternately opening and closing a portion of the crossover pipe connecting the IP section to the second LP section; and at least one extraction port for extracting a quantity of steam from at least one of the following: the crossover pipe or an exhaust of the IP section.